An Algebra For Basic Graph Patterns

Motivated by recent developments in the dataspaces, web, and personal information management communities, we outline research directions on query processing for SPARQL, the W3C recommendation language for querying RDF triple stores. The core of each SPARQL query is a basic graph pattern (BGP). BGP is a little logic for extracting subsets of related nodes in an RDF graph. In this paper we undertake a formal study of BGP with an eye towards efficient SPARQL query evaluation. Our main contributions are (1) an algebraization of BGP, and (2) first steps towards a framework for the design of structural indexes to accelerate processing of queries in this algebra.

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